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Physicochemical characteristics of ambient particles settling upon leaf surfaces of urban plants in Beijing

Journal of Environmental Sciences 2006年第5期18卷 921-926页

作者： WANG Lei liu lian-you GAO Shang-yu HASI Eerdun WANG Zhi College of Resources Science and Technology Beijing Normal University Beijing 100875 China The College of Resoures Environment and Tourism Capital Normal University Beijing 100037 China

Particulate pollution is a serious health problem throughout the world, exacerbating a wide range of respiratory and vascular illnesses in urban areas. Urban plants play an important role in reducing particulate pollution. Physicochemical characteristics of ambient particles settling upon leaf surfaces of eleven roadside plants at four sites of Beijing were studies. Results showed that density of particles on the leaf surfaces greatly varied with plant species and traffic condition. Fraxinus chiuensis, Sophora japonica Ailanthus altissima, Syringa oblata and Prunus persica, had larger densities of particles among the tall species. Due to resuspension of road dust, the densities of particles of Euonymus japonicns and Parthenocissus quinquefolia with low sampling height were 2-35 times to other taller tree species. For test plant species, micro-roughness of leaf surfaces and density of particles showed a close correlation. In general, the larger micro-roughness of leaf surfaces is, the larger density of particles is. Particles settling upon leaf surfaces were dominantly PM30 （particulate matter less than 10 μm in aerodynamic diameter; 98.4%） and PM2.5 （particulate matter less than 2.5 μm in aerodynamic diameter; 64.2%） which were closely relative to human health. Constant elements of particles were C, O, K, Ca, Si, Al, Mg, Na, Fe, S, Cl and minerals with higher content were SiO2, CaCO3, CaMg（CO3）2, NaCI and 2CASO4. H2O, SiO2. CaCO3 and CaMg（CO3）2 mainly came from resuspension of road dust. 2CaSO4. H2O was produced by the reaction between CaCO3 derived from earth dust or industrial emission and SO2, H2SO4 or sulfate. NaCl was derived from sea salt.

关键词： density of particles particle size distribution element composition micro-configuration of leaf epidermis mineral composition particles urban plants

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Development of Soil Crusts Under Simulated Rainfall and Crust Formation on a Loess Soil as Influenced by Polyacrylamide

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Pedosphere 2012年第3期22卷 415-424页

作者： HU Xia liu lian-you LI Shun-Jiang CAI Qiang-Guo LU Yan-Li GUO Jin-Rui State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875(China) Academy of Disaster Reduction and Emergency Management Beijing Normal UniversityBeijing 100875(China) Institute of Plant Nutrition and Resources Beijing Academy of Agriculture and Forestry SciencesBeijing 100097(China) Institute of Geographical Science and Natural Resources Research Chinese Academy of SciencesBeijing 100101(China)

This study evaluated the morphological characteristics and dynamic variation in characteristics of soil crust and iden-tified the relationships between soil crust and splash erosion under simulated *** effect of polyacrylamide (PAM) on soil aggregate stabilization and crust formation was also investigated.A laboratory rainfall simulation experiment was carried out using soil sample *** slices were examined under a polarized light microscopy and a scanning electron microscope (SEM).The results revealed that the soil crusts were thin and were characterized by a greater density,higher shear strength,finer porosity,and lower saturated hydraulic conductivity than the underlying *** types of crusts,i.e.,structural and depositional crusts,were *** texture was determined to be the most important soil variable influ-encing surface crust formation;depositional crust formation was primarily related to the skeleton characteristics of the soil and happened when the soil contained a high level of medium and large *** crust formation processes observed were as follows:1) The fine particles on the soil surface became spattered,leached,and then rough in response to raindrop impact and 2) the fine particles were washed into the subsoil pores while a compact dense layer concurrently formed at soil surface due to the continual compaction by the ***,the factors that influenced structural crust formation were a large amount of fine particles in the soil surface,continual impact of raindrops,dispersion of aggregates into fine particles,and the formation of a compact dense layer concurrently at the soil *** was concluded that the most important factor in the formation of soil crusts was raindrop *** polyacrylamide (PAM) was applied,it restored the soil structure and greatly increased soil aggregate *** effectively prevented crust ***,this function of PAM was not continuously effective and

关键词： depositional crust raindrop impact soil aggregates splash erosion structural crust

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Interdecadal fluctuation of dry and wet climate boundaries in China in the past 50 years

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Journal of Geographical Sciences 2002年第2期12卷 87-93页

作者： Yang Jian-ping Ding Yong-jian Chen Ren-sheng liu lian-you Cold and Arid Regions Environmental and Engineering Research Institute CAS Lanzhou China Institute of Resource and Environmental Sciences Beijing Normal University Beijing China

Based on the mean yearly precipitation and the total yearly evaporation data of 295 meteorological stations in China in 1951-1999, the aridity index is calculated in this paper. According to the aridity index, the climatic regions in China are classified into three types, namely, arid region, semi-arid region and humid region. Dry and wet climate boundaries in China fluctuate markedly and differentiate greatly in each region in the past 50 years. The fluctuation amplitudes are 20-400 km in Northeast China, 40-400 km in North China, 30-350 km in the eastern part of Northwest China and 40-370 km in Southwest China. Before the 1980s (including 1980), the climate tended to be dry in Northeast China and North China, to be wet in the eastern part of Northwest China and very wet in Southwest China. Since the 1990s there have been dry signs in Southwest China, the eastern part of Northwest China and North China. The climate becomes wetter in Northeast China. Semi-arid region is the transitional zone between humid and arid regions, the monsoon edge belt in China, and the susceptible region of environmental evolution. At the end of the 1960s dry and wet climate in China witnessed abrupt changes, changing wetness into dryness. Dry and wet climate boundaries show the fluctuation characteristics of the whole shifts and the opposite fluctuations of eastward, westward, southward and northward directions. The fluctuations of climatic boundaries and the dry and wet variations of climate have distinctive interdecadal features.

关键词： China the index of aridity dry and wet climate boundary fluctuation

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Estimation of Sand Transportation Rate for Fixed and Semi-Fixed Dunes Using Meteorological Wind Data

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Pedosphere 2009年第1期19卷 129-136页

作者： HU Xia liu lian-you LI Shun-Jiang XIAO Bi-Lin liu Mu-Xin Key Lab of Environment Change and Natural Disaster Ministry of Education Beijing Normal Univeristy Beijing 100875 （China） Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs/Ministry of Education Beijing Normal University Beijing 100875 （China） State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 21008 （China） Institute of Plant Nutrition and Resources Beijing Academy of Agriculture and Forestry Sciences Beijing 100097 （China） Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 （China）

Taibus County, Inner Mongolia, China, lies in a farming-pastoral ecotone, where severe wind erosion and various aeolian sand hazards are prevalent and fixed and semi-fixed sand dunes occur frequently. This study was conducted to investigate the relationships between sand transportation rate and wind speed for the fixed and semi-fixed sand dunes based on field measurements. The annual quantity of soil erosion by wind was estimated using meteorological wind data. The results indicated that the sand transportation rate in Taibus County in 2000 was 57.38 kg cm-1 year-1 for the semi-fixed dunes and 4.56 kg cm-1 year-1 for the fixed dunes. The total duration of erosive winds covered 12.5% of the time of the year, and spring posed the highest potential of sand transportation. Wind with low speed (≤ 17 m s-1) and high frequency plays a dominant role in sand transportation, while strong wind (≥ 17 m s-1) with low frequency significantly enhanced the sand transportation. Erosive wind speed, directions, and frequency were three crucial dynamic factors influencing sand hazards in the farming-pastoral ecotone. The dominant factors intensifying sand and dust storms in Taibus County might be related to the favorable wind condition in combination with the durable drought, which led to land desertification and vegetation degradation.

关键词： fixed and semi-fixed dunes meteorological wind data sand transportation rate wind erosion

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利用静止气象卫星数据提取沙尘信息

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中国矿业大学学报 2009年第5期38卷 751-756页

作者：周纪唐艳宫阿都刘连友北京师范大学地表过程与资源生态国家重点实验室减灾与应急管理研究院北京100875

根据静止气象卫星通道少且集中在中红外-热红外谱区的特点,将线性光谱混合模型引入沙尘提取研究中.利用相关通道的累积直方图实现端元的自动提取,结合混合像元分解结果与亮温差阈值,建立了针对风云二号C,D星遥感数据的沙尘分布信息提取... 详细信息

根据静止气象卫星通道少且集中在中红外-热红外谱区的特点,将线性光谱混合模型引入沙尘提取研究中.利用相关通道的累积直方图实现端元的自动提取,结合混合像元分解结果与亮温差阈值,建立了针对风云二号C,D星遥感数据的沙尘分布信息提取模型.结果表明:通过原始数据DN值的累积直方图进行端元自动提取,混合像元分解的结果能够实现沙尘信息增强;结合沙尘在11μm通道与12μm通道的亮温差为负及在3.7μm通道与11μm通道亮温差高于其他目标的特点,对"伪"沙尘像元进行剔除;该方法应用于2005年4月27~28日我国北方地区一次强沙尘暴过程的结果显示,该方法提取沙尘精度较高,能够客观反映沙尘运移过程.

关键词：静止气象卫星线性光谱混合模型直方图亮温沙尘

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马尾松毛虫越冬代幼虫空间分布格局研究

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安徽农业科学 2010年第23期38卷 12532-12534页

作者：刘有莲广西生态工程职业技术学院广西柳州545004

根据2008年广西沙塘林场马尾松毛虫越冬代幼虫虫口密度,采用分布型指数及回归模型法探讨了广西沙塘林场马尾松毛虫越冬代幼虫空间分布格局。结果表明,马尾松毛虫越冬代幼虫呈聚集分布,分布的基本成分为个体群。列出了林间调查最适抽样... 详细信息

根据2008年广西沙塘林场马尾松毛虫越冬代幼虫虫口密度,采用分布型指数及回归模型法探讨了广西沙塘林场马尾松毛虫越冬代幼虫空间分布格局。结果表明,马尾松毛虫越冬代幼虫呈聚集分布,分布的基本成分为个体群。列出了林间调查最适抽样数及序贯抽样分析表,提出了马尾松毛虫越冬幼虫防治的上下限指标,为害虫综合治理提供了一定的理论依据。

关键词：马尾松毛虫空间格局序贯抽样广西沙塘林场

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沙区旱作农田作物垄沟种植下土壤水分动态观测——太仆寺旗油菜种植试验结果

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干旱区资源与环境 2005年第3期19卷 120-125页

作者：刘目兴王静爱刘连友北京师范大学地理学与遥感科学学院北京师范大学资源学院北京100875

在沙区旱作农田设计了4种种植油菜的垄沟种植试验,观测了其与传统平作下的土壤重量含水率.野外对比观测表明:在油菜生长季内,垄沟种植下土壤的水分含量高于传统平作,尤其在地表0～30cm的耕作层;土壤水分在生长季内呈'双峰双谷'型波动特... 详细信息

在沙区旱作农田设计了4种种植油菜的垄沟种植试验,观测了其与传统平作下的土壤重量含水率.野外对比观测表明:在油菜生长季内,垄沟种植下土壤的水分含量高于传统平作,尤其在地表0～30cm的耕作层;土壤水分在生长季内呈'双峰双谷'型波动特征,可分为'墒情恢复期--缓慢耗墒期--墒情恢复期--迅速耗墒期--墒情恢复期'五个阶段,迅速耗墒期与油菜的旺盛生长期一致,而该时段垄沟种植下土壤重量含水率较高;在同一深度土层,垄沟种植下土壤水分的变异系数小于传统平作,土壤水分季节速变层和活跃层厚度小,稳定层靠近地表,土壤干湿波动较小.该试验研究可以为调整沙区旱地耕作方式,优化土地利用结构及风蚀防治提供参考.

关键词：土壤水分土壤重量含水率耕作方式垄沟种植稳定性油菜

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六种无公害农药对杜鹃冠网蝽的药效试验

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湖北农业科学 2011年第20期50卷 4190-4193页

作者：刘有莲黄寿昌广西生态工程职业技术学院广西柳州545004

为筛选防治杜鹃冠网蝽的无公害农药,进行了6种农药不同浓度的叶面喷雾防治药效试验。结果表明,施药后7 d,10%氟铃.毒死蜱EC、5%阿维菌素EC 500倍稀释液、1 000倍稀释液与1 500倍稀释液防治效果间有极显著差异,2.5%溴氰菊酯EC、2.5%吡虫... 详细信息

为筛选防治杜鹃冠网蝽的无公害农药,进行了6种农药不同浓度的叶面喷雾防治药效试验。结果表明,施药后7 d,10%氟铃.毒死蜱EC、5%阿维菌素EC 500倍稀释液、1 000倍稀释液与1 500倍稀释液防治效果间有极显著差异,2.5%溴氰菊酯EC、2.5%吡虫啉EC、2.5%高效氯氟菊酯EW、4.5%高效氯氟菊酯EC 2 000倍稀释液、2 500倍稀释液与3 000倍稀释液防治效果间有极显著差异。6种农药均可用于防治杜鹃冠网蝽,各农药的最佳用药浓度为:10%氟铃.毒死蜱EC 1 000倍稀释液,5%阿维菌素EC 500倍稀释液,2.5%溴氰菊酯EC、2.5%吡虫啉EC、2.5%高效氯氟菊酯EW、4.5%高效氯氟菊酯EC 2 500倍稀释液。

关键词：无公害农药杜鹃冠网蝽药效试验

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Multifunctional Nacre‑Like Nanocomposite Papers for Electromagnetic Interference Shielding via Heterocyclic Aramid/MXene Template‑Assisted In‑Situ Polypyrrole Assembly

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Nano-Micro Letters 2025年第3期17卷 37-54页

作者： Jinhua Xiong Xu Zhao Zonglin liu He Chen Qian Yan Huanxin lian Yunxiang Chen Qingyu Peng Xiaodong He National Key Laboratory of Science and Technology On Advanced Composites in Special Environments Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbin 150080People’s Republic of China

Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic *** this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.

关键词： MXene Remarkable mechanical properties Heterocyclic aramid Electromagnetic interference shielding Polypyrrole Multifunctionality

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土壤可蚀性研究述评

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干旱区地理 2006年第1期29卷 124-131页

作者：宋阳刘连友严平曹彤北京师范大学资源学院北京师范大学环境演变与自然灾害教育部重点实验室北京100875

土壤可蚀性是土壤对侵蚀作用的敏感性。对土壤可蚀性的研究是认识土壤侵蚀机理的一个重要环节。土壤可蚀性可以通过测定土壤的理化性质、水冲、模拟降雨、小区和风洞试验测定,可以使用土壤侵蚀模型与诺谟图计算土壤可蚀性。研究中产生... 详细信息

土壤可蚀性是土壤对侵蚀作用的敏感性。对土壤可蚀性的研究是认识土壤侵蚀机理的一个重要环节。土壤可蚀性可以通过测定土壤的理化性质、水冲、模拟降雨、小区和风洞试验测定,可以使用土壤侵蚀模型与诺谟图计算土壤可蚀性。研究中产生了许多可蚀性指数和计算公式。土壤可蚀性是一个相对的概念,它受空间变化、土壤性质的时间动态变化和人类活动等因素的影响。在土壤可蚀性的研究中存在着一些不足,具体表现为:农田土壤是土壤可蚀性研究的主要对象,区域之间的土壤可蚀性缺乏对比,因此加强对土壤可蚀性机理、实验与风水复合侵蚀作用下土壤可蚀性的研究有着十分重要的意义。

关键词：土壤侵蚀土壤可蚀性测定计算机理

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